Air interface for telecommunications systems with cordless telecommunications between mobile and/or stationary transmitting receiving devices

ABSTRACT

In order to improve the performance of physical channels in telecommunications systems using wire-free telecommunication between mobile and/or stationary transmitting/receiving appliances as a function of; the channel data transmission rate, the system environment, the system utilization and the distance between the transmitting/receiving appliances, such that no circuitry changes are required to the transmitters and/or receivers in the transmitting/receiving appliances, an air interface is proposed, in which the number of N PILOT  bits, N TPC  bits and N TFCI  bits are each variable, and in which, in particular during an active or passive telecommunications link between the mobile and/or stationary transmitting/receiving appliances in the telecommunications system, the number of N PILOT  bits, N TPC  bits and N TFCI  bits can each be varied and/or optimized adaptively by control means, such as by suitable “layer  2 ” or “layer  3 ” signaling (“layer  2/3 ” signaling) which takes place, for example, via the DPDCH channel.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention pertains to wireless telecommunication systems andin particular to an air interface for telecommunications systems usingwireless telecommunication between mobile and/or stationarytransmitting/receiving units.

2. Description of the Related Art

Telecommunications systems using wireless telecommunication betweenmobile and/or stationary transmitting/receiving units (appliances) arespecific message systems using a message transmission path between amessage source and a message sink, and in which, for example, basetransceiver stations and mobile units are used as transmitting andreceiving appliances for message processing and transmission and inwhich,

1) the message processing and message transmission can take place in apreferred transmission direction (simplex mode) or in both transmissiondirections (duplex mode),

2) the message processing is preferably digital,

3) the message transmission takes place over the long-distancetransmission path without wires on the basis of various messagetransmission methods for multiple use of the message transmission pathFDMA (Frequency Division Multiple Access), TDMA (Time Division MultipleAccess) and/or CDMA (Code Division Multiple Access)—for example inaccordance with radio standards such as DECT [Digital Enhanced(previously: European) Cordless Telecommunication; seeNachrichtentechnik Elektronik 42 (1992) [Information TechnologyElectronics 42 (1992)] Jan./Feb. No. 1, Berlin, DE; U. Pilger “Strukturdes DECT-Standards” [Structure of the DECT Standard], pages 23 to 29 inconjunction with the ETSI publication ETS 300175-1 . . . 9; Oct. 1992and the DECT publication from the DECT Forum, February 1997, pages 1 to16], GSM [Groupe Spéciale Mobile or Global System for MobileCommunication; see Informatik Spektrum 14 [Information Spectrum 14](1991) June, No. 3, Berlin, DE; A. Mann: “Der GSM-Standard—Grundlage fürdigitale europäische Mobilfunknetze” [The GSM Standard—basis for digitalEuropean mobile radio networks], pages 137 to 152 in conjunction withthe publication telekom praxis [Telecom Practice] 4/1993, P. Smolka“GSM-Funkschnittstelle—Elemente und Funktionen” [GSM airinterface—elements and functions], pages 17 to 24], UMTS [UniversalMobile Telecommunication System; see (1): Nachrichtentechnik Elektronik[Information Technology Electronics], Berlin 45, 1995, Issue 1, pages 10to 14 and Issue 2, pages 24 to 27; P. Jung, B. Steiner: “Konzept einesCDMA-Mobilfunksystems mit gemeinsamer Detektion für die dritteMobilfunkgeneration” [Concept of a CDMA mobile radio system with jointdetection for the third mobile radio generation]; (2):Nachrichtentechnik Elektronik [Information Technology Electronics],Berlin 41, 1991, Issue 6, pages 223 to 227 and page 234; P. W. Baier, P.Jung, A. Klein: “CDMA—ein günstiges Vielfachzugriffsverfahren fürfrequenzselektive und zeitvariante Mobilfunkkanäle” [CDMA—a usefulmultiple access method for frequency-selective and time-variant mobileradio channels]; (3): IEICE Transactions on Fundamentals of Electronics,Communications and Computer Sciences, Vol. E79-A, No. 12, December 1996,pages 1930 to 1937; P. W. Baier, P. Jung: “CDMA Myths and RealitiesRevisited”; (4): IEEE Personal Communications, February 1995, pages 38to 47; A. Urie, M. Streeton, C. Mourot: “An Advanced TDMA Mobile AccessSystem for UMTS”; (5): telekom praxis [Telecom Practice], 5/1995, pages9 to 14; P. W. Baier: “Spread-Spectrum-Technik und CDMA—eineursprünglich militärische Technik erobert den zivilen Bereich”[Spread-spectrum technology and CDMA—an originally military technologyconquers the civil area]; (6): IEEE Personal Communications, February1995, pages 48 to 53; P. G. Andermo, L. M. Ewerbring: “A CDMA-BasedRadio Access Design for UMTS”; (7): ITG Fachberichte 124 [ITG SpecialistReports] (1993), Berlin, Offenbach: VDE Verlag ISBN 3-8007-1965-7, pages67 to 75; Dr. T. Zimmermann, Siemens A G: “Anwendung von CDMA in derMobilkommunikation” [Use of CDMA in mobile communication]; (8): telcomreport 16, (1993), Issue 1, pages 38 to 41; Dr. T. Ketseoglou, Siemens AG and Dr. T. Zimmermann, Siemens A G: “Effizienter Teilnehmerzugriff fürdie 3. Generation der Mobilkommunikation—Vielfachzugriffsverfahren CDMAmacht Luftschnittstelle flexibler” [Efficient subscriber access for the3rd generation of mobile communication—the CDMA multiple access methodmakes the air interface more flexible]; (9): Funkschau [Radio Show]6/98: R. Sietmann “Ringen um die UMTS-Schnittstelle” [Ring around theUMTS interface], pages 76 to 81] WACS or PACS, IS-54, IS-95, PHS, PDC,etc. [see IEEE Communications Magazine, January 1995, pages 50 to 57; D.D. Falconer et al.: “Time Division Multiple Access Methods for WirelessPersonal Communications”].

“Message” is a generic term, which covers both the information and thephysical representation (signal). Despite a message having the sameinformation, different signal forms may occur. Thus, for example, amessage relating to a subject may be transmitted

(1) in the form of a picture,

(2) as a spoken word,

(3) as a written word,

(4) as an encrypted word or picture

The types of transmission in categories (1) through (3) are in this casenormally characterized by continuous (analog) signals, while the type oftransmission in category (4) normally comprises discontinuous signals(for example pulses, digital signals).

According, for example, to the document Funkschau [Radio Show] 6/98: R.Sietmann “Ringen um die UMTS-Schnittstelle” [Ring around the UMTSinterface], pages 76 to 81 there are two scenario elements in the UMTSscenario (3rd mobile radio generation or IMT-2000). In a first scenarioelement, the licensed coordinated mobile radio is based on a WCDMAtechnology (Wideband Code Division Multiple Access) and, as in the caseof GSM, is operated using the FDD mode (Frequency Division Duplex),while, in a second scenario element, the unlicensed uncoordinated mobileradio is based on a TD-CDMA technology (Time Division-Code DivisionMultiple Access) and, as in the case of DECT, is operated using the TDDmode (Frequency Division Duplex).

For WCDMA/FDD operation of the universal mobile telecommunicationssystem, the air interface of the telecommunications system in each casecontains a number of physical channels in the uplink and downlinktelecommunications directions in accordance with the document ETSI STCSMG2 UMTS-L1, Tdoc SMG2 UMTS-L1 163/98: “UTRA Physical Layer DescriptionFDD Parts” Vers. 0.3, May 29, 1998 of which a first physical channel,the so-called Dedicated Physical Control CHannel DPCCH and a secondphysical channel, the so-called Dedicated Physical Data CHannel DPDCH,[lacuna] with respect to a “three-layer structure” composed of 720 mslong (T_(MZR)=720 ms) super frames MZR, 10 ms long (T_(FZR)=10 ms) timeframes (radio frames) ZR and 0.625 ms long (T_(ZS)=0.625 ms) time slotsZS, which are illustrated in FIGS. 1 and 2. Each super frame MZRcontains, for example, 72 time frames ZR, while each time frame ZR inturn has, for example, 16 time slots ZS1 . . . ZS16. As a burststructure for the first physical channel DPCCH, the individual time slotZS, ZS1 . . . ZS16 (burst) has a pilot sequence PS with a numberN_(PILOT) of bits (N_(PILOT) bits) for channel estimation, a TPCsequence TPCS with a number N_(TPC) of bits (N_(TPC) bits), inparticular for rapid power control (Traffic Power Control), and a TFCIsequence TFCIS with a number N_(TFCI) of bits (N_(TFCI) bits) fortraffic format channel indication, which indicate the bit rate, the typeof service, the type of error protection coding, etc., and, for thesecond physical channel DPDCH, has a user data sequence NDS with anumber N_(DATA) of user data bits (N_(DATA) bits). Table 1, below,contains the bit values specified in table 3.2.2-4 by the ARIB in theARIB publication “Specifications of Air-Interface for a 3G MobileSystem”, Volume 3, June 1998 for the DPDCH channel and the DPCCH channelwith the bit subdivisions N_(PILOT), N_(TPC), N_(TFCI) for channel bitrates of 64 and 128 kbit/s, respectively.

Bits/time slot Channel bit Channel symbol Spread Bits/frame DPCCH rate(kbps) rate (ksps) factor DPDCH DPCCH Total DPDCH N_(TFCI) N_(TPC)N_(PILOT) 64 32 128 480 160 640 40 30 0 2 8 64 32 128 448 192 640 40 282 2 8 128 64 64 1120 160 1280 80 70 0 2 8 128 64 64 1088 192 1280 80 682 2 8

In the “downlink” (downward telecommunications direction; radio linkfrom the base transceiver station to the mobile station) in theWCDMA/FDD system from ETSI and ARIB—FIG. 1—the first physical channel[“Dedicated Physical Control Channel (DPCCH)] and the second physicalchannel [“Dedicated Physical Data Channel (DPDCH)] are time-divisionmultiplexed while, in the “uplink” (upward telecommunications direction;radio link from the mobile station to the base transceiver station)—FIG.2—I/Q multiplexing is used, in which the second physical channel DPDCHis transmitted in the I channel, and the first physical channel DPCCH istransmitted in the Q channel.

For TDCDMA/TDD operation of the universal mobile telecommunicationssystem, the air interface of the telecommunications system in the uplinkand downlink telecommunications directions is once again based, inaccordance with the document TSG RAN WG1 (S1.21): “3^(rd) GenerationPartnership Project (3GPP)” Vers. 0.0.1, 1999-01, on the “three-layerstructure” consisting of the super frames MZR, the time frames ZR andthe time slots ZS, for all the physical channels, which is illustratedin FIG. 3. Each super frame MZR in turn contains, for example, 72 timeframes, while each time frame ZR in turn has, for example, the 16 timeslots ZS1 . . . ZS16. The individual time slot ZS, ZS1 . . . ZS16(burst) has either, in accordance with the ARIB proposal, a first timeslot structure (burst structure) ZSS1 in the sequence comprising a firstuser data sequence NDS1 with N_(DATA1) bits, the pilot sequence PS withN_(PILOT) bits for channel estimation, the TPC sequence TPCS withN_(TPC) bits for power control, the TFCI sequence TFCIS with N_(TFCI)bits for traffic format channel indication, a second user data sequenceNDS2 with N_(DATA2) bits and a guard period SZZ with N_(GUARD) bits or,in accordance with the ETSI proposal, a second time slot structure(burst structure) ZSS2 in the sequence comprising the first user datasequence NDS1, a first TFCI sequence TFCIS1, a midamble sequence MIS forchannel estimation, a second TFCI sequence TFCIS2, the second user datasequence NDS2 and the guard period SZZ.

FIG. 4 shows, for example, on the basis of a GSM radio scenario having,for example, two radio cells and base transceiver stations arranged inthem, with a first base transceiver station BTS1 (transmitter/receiver)omnidirectionally illuminating a first radio cell FZ1, and a second basetransceiver station BTS2 (transmitting/receiving appliance)omnidirectionally illuminating a second radio cell FZ2 and, based onFIGS. 1 and 2, a radio scenario with multiple channel utilization usingfrequency/time/code-division multiplexing, in which the base transceiverstations BTS1, BTS2 are connected or can be connected via an airinterface designed for the radio scenario to a number of mobile stationsMS1 through MS5 (transmitting/receiving units) located in the radiocells FZ1, FZ2 by wire-free unidirectional or bidirectional—uplinkdirection UL and/or downlink direction DL—telecommunication tocorresponding transmission channels TRC. The base transceiver stationsBTS1, BTS2 are connected in a known manner (see GSM telecommunicationssystem) to a base transceiver station controller BSC, which carries outthe frequency administration and switching functions in order to controlthe base transceiver stations. For its part, the base transceiverstation controller BSC is connected via a mobile switching center MSC tothe higher-level telecommunications network, for example to the PSTN(Public Switched Telecommunication Network) The mobile switching centerMSC is the administration center for the described telecommunicationssystem. It carries out all call administration and, using attachedregisters (not shown), carries out the authentication oftelecommunications subscribers as well as location monitoring in thenetwork.

FIG. 5 shows the basic design of the base transceiver station BTS1,BTS2, which is in the form of a transmitting/receiving appliance, whileFIG. 6 shows the basic design of the mobile station MS1 through MS5,which is likewise in the form of a transmitting/receiving appliance. Thebase transceiver station BTS1, BTS2 transmits and receive radio messagesfrom and to the mobile station MS1 through MS5, while the mobile stationMS1 . . . MS5 transmits and receives radio messages from and to the basetransceiver station BTS1, BTS2. For this purpose, the base transceiverstation has a transmitting antenna SAN and a receiving antenna EAN,while the mobile station MS1 through MS5 has an antenna ANT which isused for both transmitting and receiving and can be controlled by anantenna switching circuit AU. In the uplink direction (reception path),the base transceiver station BTS1, BTS2 receives (via the receivingantenna EAN), for example, at least one radio message FN with afrequency/time/code component of at least one of the mobile stations MS1through MS5, while, in the downlink direction (reception path), themobile station MS1 through MS5 receives (via the common antenna ANT),for example at least one radio message FN with a frequency/time/codecomponent of at least one base transceiver station BTS1, BTS2. The radiomessage FN in this case comprises a carrier signal spread over a broadbandwidth and with information composed of data symbols modulated ontoit.

A radio receiving device FEE (receiver) is used to filter the receivedcarrier signal and to mix it down to an intermediate frequency which,for its part, is subsequently sampled and digitized. Afteranalog/digital conversion, the signal, which has been subject todistortion by multipath propagation on the radio path, is fed to anequalizer EQL, which compensates for the majority of the distortion(keyword: synchronization).

A channel estimator KS then attempts to estimate the transmissioncharacteristics of the transmission channel TRC on which the radiomessage FN has been transmitted. The transmission characteristics of thechannel are in this case indicated by means of the channel impulseresponse in the time domain. To make it possible to estimate the channelimpulse response, the radio message FN is allocated or assigned, at thetransmitting end (in the present case by the mobile station MS1 throughMS5 or the base transceiver station BTS1, BTS2), a specific additionalinformation item, which is constructed as a training informationsequence and is in the form of a so-called midamble.

A data detector DD, which is downstream from this and is common to allthe received signals, is used to equalize and separate the individualmobile-station-specific signal elements contained in the common signal,in a known manner. After equalization and separation, the data symbolswhich have been present up to this point are converted in asymbol-to-data converter SDW into binary data. After this, a demodulatorDMOD is used to obtain the original bit stream from the intermediatefrequency before, in a demultiplexer DMUX, the individual time slots areallocated to the correct logical channels, and thus also to the variousmobile stations.

The received bit sequence is decoded channel-by-channel in a channelcodec KC. Depending on the channel, the bit information is assigned tothe monitoring and signaling time slot or to a voice time slot and—inthe case of the base transceiver station (FIG. 5)—the monitoring andsignaling data and the voice data for transmission to the basetransceiver station controller BSC are jointly transferred to aninterface SS which is responsible for signaling and voicecoding/decoding (voice codec), while—in the case of the mobile station(FIG. 6)—the monitoring and signaling data are transferred to a controland signaling unit STSE, which is preferably in the form of amicroprocessor μP and is responsible for all the mobile stationsignaling and control, and the voice data are transferred to a voicecodec SPC which is designed for voice inputting and outputting. Themicroprocessor μP contains a program module PGM which is designed on thebasis of the ISO layer model [see: Unterrichtsblätter [Trainingsheets]—Deutsche Telekom, Year 48, 2/1995, pages 102 to 111] and inwhich the air interface protocol for the UMTS scenario is handled. Ofthe layers defined in the layer model, only the first four layers, whichare essential for the mobile station, are shown; a first layer S1, asecond layer S2, a third layer S3 and a fourth layer S4, with the firstlayer S1 containing, inter alia, the DPCCH channel and the DPDCHchannel.

In the voice codec of the interface SS in the base transceiver stationBTS1, BTS2, the voice data in a predetermined data stream become[lacuna] (for example 64 kbit/s stream in the network direction, and a13 kbit/s stream from the network direction).

The base transceiver station BTS1, BTS2 is controlled entirely in acontrol unit STE, which is preferably in the form of a microprocessorμP. The microprocessor μP once again contains the program module PGMwhich is designed on the basis of the ISO layer model [see:Unterrichtsblätter—Deutsche Telekom, Year 48, 2/1995, pages 102 to 111]and in which the air interface protocol for the UMTS scenario ishandled. Of the layers defined in the layer model, once again only thefirst four layers, which are essential for the base transceiver station,are shown; the first layer S1, the second layer S2, the third layer S3and the fourth layer S4, with the first layer S1 containing, inter alia,the DPCCH channel and the DPDCH channel.

In the downlink direction (transmission path), the base transceiverstation BTS1, BTS2 transmits (via the transmitting antenna SAN), forexample, at least one radio message FN with a frequency/time/codecomponent to at least one of the mobile stations MS1 through MS5, while,in the uplink direction (transmission path), the mobile station MS1through MS5 transmits (via the common antenna ANT), for example, atleast one radio message FN with a frequency/time/code component to atleast one base transceiver station BTS1, BTS2.

In the base transceiver station BTS1, BTS2 in FIG. 5, the transmissionpath thus starts in such a way that monitoring and signaling data whichare received from the base transceiver station controller BSC via theinterface SS, together with voice data, are assigned in the channelcodec KC to a monitoring and signaling time slot or to a voice timeslot, respectively, and these are coded channel-by-channel into a bitsequence.

In the mobile station MS1 through MS5 in FIG. 6, the transmission pathstarts in such a way that voice data received from the voice codec SPCand monitoring and signaling data received from the control andsignaling unit STSE are assigned, in the channel codec KC, to amonitoring and signaling time slot or to a voice time slot,respectively, and these are coded channel-by-channel into a bitsequence.

The bit sequence obtained in the base transceiver on BTS1, BTS2 and inthe mobile station MS1 through MS5 is converted into data symbols in ineach case one data-to-symbol converter DSW. Subsequently, the datasymbols are in each case spread in a spreading device SPE using arespectively subscriber-specific code. After this, in the burstgenerator BG which comprises a burst compiler BZS and a multiplexer MUX,a training information sequence in the form of a midamble is added toeach of the spread data symbols in the burst compiler BZS, for channelestimation, and the burst information obtained in this way is placed inthe correct time slot in the multiplexer MUX. Finally, the burst thathas been obtained is in each case radio-frequency-modulated in amodulator MOD and is digital/analog converted before the signal obtainedin this way is transmitted as a radio message FN via a radiotransmitting device FSE (transmitter) to the transmitting antenna SAN orto the joint antenna ANT.

TDD telecommunications systems (Time Division Duplex) aretelecommunications systems in which the transmission time frame,comprising a number of time slots, is split—preferably in the center—forthe downlink transmission direction and the uplink transmissiondirection.

One TDD telecommunications system which has such a transmission timeframe is, for example, the known DECT system [Digital Enhanced(previously: European) Cordless Telecommunication; seeNachrichtentechnik Elektronik [Information Technology Electronics] 42(1992) Jan./Feb. No. 1, Berlin, DE; U. Pilger “Struktur desDECT-Standards” [Structure of the DECT Standard], pages 23 to 29 inconjunction with the ETSI publication ETS 300175-1 . . . 9, October 1992and the DECT publication from the DECT Forum, February 1997, pages 1 to16]. The DECT system has a DECT transmission time frame with a timeduration of 10 ms, consisting of 12 downlink time slots and 12 uplinktime slots. For any given bidirectional telecommunications link at agiven frequency in the downlink transmission direction DL and in theuplink transmission direction UL, a free time slot pair with a downlinktime slot and an uplink time slot is chosen, in accordance with the DECTStandard, in which the separation between the downlink time slot and theuplink time slot, likewise in accordance with the DECT Standard, is halfthe length (5 ms) of the DECT transmission time frame.

FDD telecommunications systems (Frequency Division Duplex) aretelecommunications systems in which the time frame, comprising a numberof time slots, for the downlink transmission direction is transmitted ina first frequency band, and that for the uplink transmission directionis transmitted in a second frequency band.

One FDD telecommunications system which transmits the time frame in thisway is, for example, the known GSM system [Groupe Spéciale Mobile orGlobal System for Mobile Communication; see Informatik Spektrum[Information Spectrum] 14 (1991) June, No. 3, Berlin, DE; A. Mann: “DerGSM-Standard—Grundlage für digitale europäische Mobilfunknetze” [The GSMStandard—basis for digital European mobile radio networks], pages 137 to152 in conjunction with the publication telekom praxis [TelecomPractice] 4/1993, P. Smolka “GSM-Funkschnittstelle—Elemente undFunktionen” [GSM radio interface—elements and functions], pages 17 to24].

The air interface for the GSM system knows a large number of logicalchannels, which are referred to as bearer services, for example an AGCHchannel (Access Grant CHannel), a BCCH channel (BroadCast CHannel), anFACCH channel (Fast Associated Control CHannel), a PCH channel (PagingCHannel), an RACH channel (Random Access CHannel) and a TCH channel(Traffic CHannel), whose respective function in the air interface isdescribed, for example, in the document Informatik Spektrum [InformationSpectrum] 14 (1991) June, No. 3, Berlin, DE; A. Mann: “DerGSM-Standard—Grundlage für digitale europäische Mobilfunknetze” [The GSMStandard—basis for digital European mobile radio networks], pages 137 to152 in conjunction with the publication telekom praxis [TelecomPractice] 4/1993, P. Smolka “GSM-Funkschnittstelle—Elemente undFunktionen” [GSM radio interface—elements and functions], pages 17 to24.

Since, in particular, WCDMA/FDD operation and TDCDMA/TDD operation areintended to be used jointly for the purposes of the UMTS scenario (3rdmobile radio generation or IMT-2000), good telecommunications systemperformance is desirable in both the downlink direction and the uplinkdirection, that is to say a good bit error rate as a function of thesignal-to-noise ratio.

The performance in the downlink and uplink directions is dependent,inter alia, on the channel estimation, rapid power control and detectionof the format bits.

The quality of channel estimation, the functionality of rapid powercontrol and the detection of the format bits are dependent on thenumbers N_(PILOT), N_(TPC) and N_(TFCI) and the energy in therespectively available bits.

The performance in the downlink and uplink directions may therefore beless than optimum for a chosen value triple N_(PILOT), N_(TPC) andN_(TFCI).

If, for example, the number of N_(PILOT) bits is too low, then toolittle energy is available for channel estimation. This causes “poor”channel estimation and/or a worse (higher) bit error rate in thereceiver, that is to say the performance in the downlink and uplinkdirections is worse. A similar situation applies to N_(TPC) bits forrapid power control and the N_(TFCI) bits for traffic format channelindication.

The optimum value triple is dependent on the channel bit rate, theenvironment (city area, rural area, hilly area, in-house), the distancebetween the mobile station and the base transceiver station, the loadlevel on the WCDMA/FDD system (number of active links, disturbance byinterference from adjacent cells, etc.).

Normally, the value triple N_(PILOT), N_(TPC) and N_(TFCI) is fixed fora specific channel bit rate and cannot be varied during a link or duringthe handover to a different area.

According to the document ETSI STC SMG2 UMTS-L1, Tdoc SMG2 UMTS-L1168/98: “Flexible Power Allocation for Downlink DPCCH Fields”, June15-17, 1998, Turin, Italy, the pilot bits, the bits for rapid powercontrol and the format bits are transmitted by the base transceiverstation at a higher power level than the data bits in the DPDCH. Adisadvantage in this case is that the AGC and the A/D converter for thedata bits in the DPDCH channel are no longer operated at an optimumlevel in the receiving appliance. A further disadvantage is that theradio section in the transmitting appliance must be designed for astep-function increase/decrease in the transmitted power level.Advantageously, the number of data bits in the DPDCH channel does notchange.

EP-0627827 A2 discloses a method for controlling the transmission ofinformation streams at a variable rate in radio systems, in whichavailable bits are allocated dynamically to the variable-rateinformation streams which originate from different sources in the systemand which are transmitted on the same radio channel related to the samecommunication link, taking account of a number of system characteristicsand system parameters.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following FIGS. 1 to 7:

FIG. 1 shows a “three-layer structure” of a WCDMA/FDD air interface inthe “downlink”,

FIG. 2 shows a “three-layer structure” of a WCDMA/FDD air interface inthe “uplink”,

FIG. 3 shows a “three-layer structure” of a TDCDMA/TDD air interface,

FIG. 4 shows a radio scenario with channel multiple use based onfrequency/time/code division multiplex,

FIG. 5 shows the basic design of a base transceiver station in the formof a transmitting/receiving appliance,

FIG. 6 shows the basic design of a mobile station, which is likewise inthe form of a transmitting/receiving appliance, and

FIG. 7 shows a modified microprocessor, based on the microprocessorillustrated in FIGS. 5 and 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The object on which the invention is based is to improve the performanceof physical channels in 35 telecommunications systems using wire-freetelecommunication between mobile and/or stationarytransmitting/receiving appliances, as a function of the channel datatransmission rate, the system environment, the system load level and thedistance between the transmitting/receiving appliances, such that nocircuitry changes are required to the transmitter and/or receiver in thetransmitting/receiving appliances.

This object is in each case achieved by an air interface having aphysical first layer (S1) of the air interface (PGM) that contains afirst physical channel (DPCCH) and a second physical channel (DPDCH) inat least one time slot (ZS) of a time frame structure (ZR, MZR) of thetelecommunications system for each telecommunications link which isallocated to the first layer (S1). The first channel (DPCCH) contains afirst data field for channel estimation (PS)—using channel estimationdata (N_(PILOT))—, a second data field for power control (TPCS)—usingpower control data (N_(TPC))—and a third data field for traffic formatchannel indication (TFCIS)—using traffic format channel indication data(N_(TFCI)). Furthermore, the second channel (DPDCH) contains a user datafield (NDS) with user data (N_(DATA), N_(DATA1), N_(DATA2)) A secondlayer (S2) which is responsible for data security and/or a third layer(S3) which is responsible for switching, of the air interface (PGM) eachcontain control means (STM) which are designed to access the physicalchannels (DPCCH, DPDCH) such that the distribution of the data(N_(PILOT), N_(TPC)/ N_(TFCI)) in the data fields (PS, TPCS, TFCIS)during the telecommunications link can be varied in the uplink and/ordownlink telecommunications directions, by adaptation to characteristicsof the telecommunications link. This is done while the amount of data inthe user data field (NDS) and the total amount of data per time slot(ZS) remain constant.

The present invention proposes an air interface in which the number ofN_(PILOT) bits, N_(TPC) bits and N_(TFCI) bits is in each case variableand in which, particularly while there is an active or passivetelecommunications link between mobile and/or stationarytransmitting/receiving appliances in the telecommunications system, thenumber of N_(PILOT) bits, N_(TPC) bits and N_(TFCI) bits can in eachcase be varied and optimized adaptively by control means, for example bysuitable “layer 2” or “layer 3” signaling (“layer 2/3” signaling) whichtakes place, for example, via the DPDCH channel.

The distribution of the data, of the N_(PILOT) bits, N_(TPC) bits andN_(TFCI) bits, in the DPCCH channel can be varied by adaptation tocharacteristics of the telecommunications link, during thetelecommunications link in the uplink and/or downlink telecommunicationsdirections, with the amount of data in the DPDCH channel remainingconstant and the amount of data per time slot remaining constant. Thevariation can in this case also be carried out to such an extent that atleast one bit type of said bits temporarily (for example for theduration of the corresponding telecommunications link) does not occur inthe DPCCH channel, that is to say the number of corresponding bits inthe DPCCH channel is equal to zero. In another embodiment of the presentinvention, the distribution of the data, of the N_(PILOT) bits, N_(TPC)bits and N_(TFCI) bits, in the DPCCH channel can be varied during thetelecommunications link in the uplink and/or downlink telecommunicationsdirections by increasing the total amount of data per time slot.

This increase can be achieved in an advantageous manner in that thetotal amount of data per time slot is increased by reducing the spreadfactor.

Furthermore, in another embodiment of the present invention, thedistribution of the data, of the N_(PILOT) bits, N_(TPC) bits andN_(TFCI) bits, in the DPCCH channel can be varied during thetelecommunications link in the downlink telecommunications directionwith the total amount of data per time slot remaining constant, in thatsome of the N_(PILOT) bits, N_(TPC) bits and N_(TFCI) bits in the DPCCHchannel are allocated to the DPDCH channel, or some of the user bits(user data) in the DPDCH channel are allocated to the DPCCH channel.

Accordingly it is possible to increase or to decrease the number ofN_(PILOT) bits, N_(TPC) bits and N_(TFCI) bits by omitting or addinguser bits or user data in the DPDCH channel.

Other embodiments of the present invention are based on the generalfundamental idea, of making use of the fact and the circumstance that,in accordance with International Application PCT/DE98/02894, estimatedchannel impulse responses are correlated with one another, with theextent of correlation itself being correlated with the relative movement(slow or fast) of the mobile transmitting/receiving appliance or of themobile station—(during slow movement, there is a strong correlationbetween the estimated channel impulse responses, while during fastmovement there is a weak correlation between the estimated channelimpulse responses)—and can be detected by the stationary and/or themobile transmitting/receiving appliance, in that, for example, channelimpulse responses from previous time slots are estimated by thestationary and/or the mobile transmitting/receiving appliance.

The present invention offers the advantage that—when a mobiletransmitting/receiving appliance (a mobile station) is moving veryslowly at a speed of less than 3 km/h (for example a data terminal withremote e-mail access) and when the channel estimation can beconsiderably improved on the basis of the above general basicconsiderations—the number of N_(Pilot) bits can be reduced withoutnoticeably adversely affecting the quality of channel estimation. Inthis case, the number of N_(TFCI) bits for traffic format channelindication and/or the number of N_(TPC) bits for rapid power control canbe increased. Overall, this improves the performance of thetelecommunications system both in the downlink direction and in theuplink direction.

This offers the advantage that—when, taking account of the above generalbasic considerations, a mobile transmitting/receiving appliance (amobile station) is moving very fast at a speed of more than 150 km/h andwhen the rapid power control can no longer compensate for the Rayleighfading (rapid fading, essentially caused by the movement of the mobilestation) and, in consequence, only the log normal fading can still becontrolled (slow fading, essentially caused by shadowing effects), inwhich case the log normal fading can be controlled using a considerablylower bit rate than that for rapid power control—the N_(TPC) bits, forexample, for rapid power control are now transmitted only in every tenthtime slot. The N_(TPC) bits for rapid power control are omitted in theother time slots. Additional N_(PILOT) bits for channel estimationand/or N_(TFCI) bits for traffic format channel indication are thentransmitted for this purpose.

Furthermore, the present invention offers the additional advantage thatwhen a mobile transmitting/receiving appliance (a mobile station) isinitially moving very slowly, the number of N_(PILOT) bits, of N_(TFCI)bits and of N_(TPC) bits used in this development is in each case usedinitially and that when—the mobile transmitting/receiving appliance (themobile station) starts to move faster and faster, the number ofN_(Pilot) bits, of N_(TFCI) bits and of N_(TPC) bits used in thisdevelopment is in each case used once a predetermined speed, for example100 km/h, has been exceeded.

The inventions are explained using an exemplary embodiment and withreference to FIG. 7.

That shows a modified microprocessor μP′ with a modified program modulePGM′, based on the microprocessor μP illustrated in FIGS. 5 and 6. Themodification consists in the modified program module PGM′ in each casecontaining control means STM in the second layer S2 which is responsiblefor data security, and in the third layer S3 which is responsible forswitching. These control means STM are designed in such a way and accessthe physical channels DPCCH, DPDCH in layer 1 in such a way that

1. the distribution of the N_(PILOT) bits in the pilot sequence PS, ofthe N_(TPC) bits in the TPC sequence TPCS and of the N_(TFCI) bits inthe TFCI sequence TFCIS during the telecommunications link in the uplinkand/or downlink telecommunications directions can be varied byadaptation to characteristics of the telecommunications link, with theamount of data in the user data sequence NDS remaining constant, andwith the total amount of data per time slot ZS remaining constant,and/or

2. the distribution of the N_(PILOT) bits in the pilot sequence PS, ofthe N_(TPC) bits in the TPC sequence TPCS and of the N_(TFCI) bits inthe TFCI sequence TFCIS during the telecommunications link in the uplinkand/or downlink telecommunications directions can be varied byincreasing the total amount of data per time slot ZS, and/or

3. the distribution of the N_(PILOT) bits in the pilot sequence PS, ofthe N_(TPC) bits in the TPC sequence TPCS and of the N_(TFCI) bits inthe TFCI sequence TFCIS during the telecommunications link in the uplinkand/or downlink telecommunications directions can be varied, with thetotal amount of data per time slot ZS remaining constant, in that someof the N_(PILOT) bits in the pilot sequence PS, of the N_(TPC) bits inthe TPC sequence TPCS and of the N_(TFCI) bits in the TFCI sequenceTFCIS are allocated to the DPDCH channel, or some of the N_(DATA) bits,of the N_(DATA1) bits and of the N_(DATA)2 bits in the user sequence NDSare allocated to the DPCCH channel.

Furthermore, it is possible for the control means STM to be designed insuch a way and to access the physical channels DPCCH, DPDCH in layer 1in such a way that

4. the number of N_(PILOT) bits in the pilot sequence PS is reduced infavor of the number of N_(TPC) bits in the TPC sequence TPCS and/or thenumber of N_(TFCI) bits in the TFCI sequence TFCIS when, as a firstcharacteristic of the telecommunications link, the mobiletransmitting/receiving appliance MS1 through MS5 is moving at a slowspeed of significantly less than 5 km/h, and/or

5. the number of N_(TPC) bits in the TPC sequence TPCS is reduced infavor of the number of N_(PILOT) bits in the pilot sequence PS and/orthe number of N_(TFCI) bits in the TFCI sequence TFCIS when, as a secondcharacteristic of the telecommunications link, the mobiletransmitting/receiving appliance MS1 . . . MS5 is moving at a high speedof significantly more than 100 km/h.

Although various minor changes and modifications might be proposed bythose skilled in the art, it will be understood that our wish is toinclude within the claims of the patent warranted hereon all suchchanges and modifications as reasonably come within our contribution tothe art.

We claim:
 1. An air interface for telecommunications systems utilizingwireless telecommunication between at least one of stationarytransmitting/receiving units and mobile transmitting/receiving units,comprising: a physical first layer that includes at least one firstphysical channel and at least one second physical channel in at leastone time slot, said at least one time slot being part of a time framestructure of the telecommunications system for each of atelecommunications link that is allocated to said physical first layer,said at least one first physical channel including a first data fieldfor channel estimation utilizing channel estimation data, said at leastone first physical channel further including a second data field forpower control utilizing power control data, said at least one firstphysical channel further including a third data field for traffic formatchannel indication utilizing traffic format channel indication data,said at least one second physical channel includes a user data fieldwith user data; at least one of a second layer and a third layer, saidsecond layer being responsible for data security, said third layer beingresponsible for switching; a control in at least one of said secondlayer and said third layer that accesses the at least one first physicalchannel and the at least one second physical channel, said controlcontrolling distribution of the channel estimation data and the powercontrol data and the traffic format channel indication data among thefirst data field and the second data field and the third data field soas to be varied in at least one of an uplink and a downlinktelecommunication direction, said distribution being adapted to thecharacteristics of said telecommunications link while amount of data inthe user data field remains constant and a total amount of data per saidat least one time slot also remains constant.
 2. An air interface fortelecommunications systems utilizing wireless telecommunication betweenat least one of stationary transmitting/receiving units and mobiletransmitting/receiving units, comprising: a physical first layer thatincludes at least one first physical channel and at least one secondphysical channel in at least one time slot, said at least one time slotbeing part of a time frame structure of the telecommunications systemfor each of a telecommunications link that is allocated to said physicalfirst layer, said at least one first physical channel including a firstdata field for channel estimation utilizing channel estimation data,said at least one first physical channel further including a second datafield for power control utilizing power control data, said at least onefirst physical channel further including a third data field for trafficformat channel indication utilizing traffic format channel indicationdata, said at least one second physical channel includes a user datafield with user data; at least one of a second layer and a third layer,said second layer being responsible for data security, said third layerbeing responsible for switching; a control in at least one of saidsecond layer and said third layer that accesses the at least one firstphysical channel and the at least one second physical channel, saidcontrol controlling a distribution of the channel estimation data andthe power control data and the traffic format channel indication dataamong the first data field and the second data field and the third datafield so as to be varied in at least one of an uplink and a downlinktelecommunication direction, with a total amount of data per time slotremaining constant, at least one of first data in data fields beingallocated to the second channel and the user data in the user data fieldbeing allocated to the first channel, said first data including thepower estimation data and the power control data and the traffic formatchannel indication data.
 3. An air interface according to claim 2,wherein the control varies the distribution by reducing number of datain the first data field in favor of at least one of data items in thesecond data field and the third data field provided that said at leastone of mobile transmitting/receiving units is moving at a speed ofsubstantially less than 5 kilometers per hour.
 4. An air interfaceaccording to claim 3, wherein the control varies the distribution byreducing number of data in the second data field in favor of at leastone of data items in the first data field and the third data fieldprovided that said at least one of mobile transmitting/receiving unitsis moving at a speed of substantially more than 100 kilometers per hour.5. An air interface according to claim 2, wherein the telecommunicationssystem is being operated in at least one of a FDD mode and a TDD mode.6. An air interface according to claim 2, wherein the telecommunicationssystem is being operated in a broadband mode.
 7. An air interfaceaccording to claim 2, wherein the control varies the distribution byincreasing a total amount of data per the at least one time slot in atleast one of an uplink and down link telecommunication directions.
 8. Anair interface according to claim 1, wherein the control varies thedistribution with the total number of data per time slot remainingconstant, at least one of first data in data fields being allocated tothe second channel and the user data in the user data field beingallocated to the first channel, said first data including the powerestimation data and the power control data and the traffic formatchannel indication data.